package com.i_art_engineer.meigong.widget;

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.animation.TranslateAnimation;
import android.widget.ImageView;

/**
 * 继承ImageView 实现了多点触碰的拖动和缩放  
 * @author lihua
 */
public class PinTuView extends ImageView {


    static final int NONE = 0;
    static final int DRAG = 1;     //拖动中    
    static final int ZOOM = 2;     //缩放中    
    static final int BIGGER = 3;   //放大ing    
    static final int SMALLER = 4;  //缩小ing    
    private int mode = NONE;       //当前的事件     

    private float beforeLenght;   //两触点距离    
    private float afterLenght;    //两触点距离    
    private float scale = 0.04f;  //缩放的比例 X Y方向都是这个值 越大缩放的越快    

    private int screenW;
    private int screenH;

    /*处理拖动 变量 */
    private int start_x;
    private int start_y;
    private int stop_x ;
    private int stop_y ;

    private TranslateAnimation trans; //处理超出边界的动画    

    /**
     * 默认构造函数
     * @param context
     */
    public PinTuView(Context context){
        super(context);
    }
    /**
     * 该构造方法在静态引入XML文件中是必须的
     * @param context
     * @param paramAttributeSet
     */
    public PinTuView(Context context,AttributeSet paramAttributeSet){
        super(context,paramAttributeSet);
    }
    /**
     * 该构造函数在动态创建时，指定图片的初始高宽
     * @param context
     * @param w
     * @param h
     */
    public PinTuView(Context context,int w,int h) {
        super(context);
        this.setPadding(0, 0, 0, 0);
        screenW = w;
        screenH = h;
    }

    /**
     * 就算两点间的距离  
     */
    private float spacing(MotionEvent event) {
        float x = event.getX(0) - event.getX(1);
        float y = event.getY(0) - event.getY(1);
        return (float)Math.sqrt(x * x + y * y);
    }

    /**
     * 处理触碰..  
     */
    @Override
    public boolean onTouchEvent(MotionEvent event)
    {
        switch (event.getAction() & MotionEvent.ACTION_MASK) {
            case MotionEvent.ACTION_DOWN:
                mode = DRAG;
                stop_x = (int) event.getRawX();
                stop_y = (int) event.getRawY();
                start_x = (int) event.getX();
                start_y = stop_y - this.getTop();
                if(event.getPointerCount()==2)
                    beforeLenght = spacing(event);
                break;
            case MotionEvent.ACTION_POINTER_DOWN:
                if (spacing(event) > 10f) {
                    mode = ZOOM;
                    beforeLenght = spacing(event);
                }
                break;
            case MotionEvent.ACTION_UP:   
            /*判断是否超出范围     并处理*/
                int disX = 0;
                int disY = 0;
                //不处理边界问题
//                if(getHeight()<=screenH || this.getTop()<0)
//                {
//                    if(this.getTop()<0 )
//                    {
//                        int dis = getTop();
//                        this.layout(this.getLeft(), 0, this.getRight(), 0 + this.getHeight());
//                        disY = dis - getTop();
//                    }
//                    else if(this.getBottom()>screenH)
//                    {
//                        disY = getHeight()- screenH+getTop();
//                        this.layout(this.getLeft(), screenH-getHeight(), this.getRight(), screenH);
//                    }
//                }

                if(this.getRight()<0)
                {
                    disX = getLeft();
                    this.layout(0, this.getTop(), 0+getWidth(), this.getBottom());
                }
                else if(getWidth()<=screenW)
                {
                   if(this.getRight()>screenW)
                    {
                        disX = getWidth()-screenW+getLeft();
                        this.layout(screenW-getWidth(), this.getTop(), screenW, this.getBottom());
                    }
                }
                if(disX!=0 || disY!=0)
                {
                    trans = new TranslateAnimation(disX, 0, disY, 0);
                    trans.setDuration(500);
                    this.startAnimation(trans);
                }
                mode = NONE;
                break;
            case MotionEvent.ACTION_POINTER_UP:
                mode = NONE;
                break;
            case MotionEvent.ACTION_MOVE:   
                /*处理拖动*/
                if (mode == DRAG) {
                    if(Math.abs(stop_x-start_x-getLeft())<88 && Math.abs(stop_y - start_y-getTop())<85)
                    {

                        this.setPosition(stop_x - start_x, stop_y - start_y, stop_x + this.getWidth() - start_x, stop_y - start_y + this.getHeight());
                        stop_x = (int) event.getRawX();
                        stop_y = (int) event.getRawY();

                    }else{
                        this.setPosition(stop_x - start_x-this.getWidth(), stop_y - start_y, stop_x - start_x, stop_y - start_y + this.getHeight());
                        stop_x = (int) event.getRawX();
                        stop_y = (int) event.getRawY();
                    }
                }    
                /*处理缩放*/
                /*
                else if (mode == ZOOM) {
                    if(spacing(event)>10f)
                    {
                        afterLenght = spacing(event);
                        float gapLenght = afterLenght - beforeLenght;
                        if(gapLenght == 0) {
                            break;
                        }
                        else if(Math.abs(gapLenght)>5f)
                        {
                            if(gapLenght>0) {

                                this.setScale(scale,BIGGER);
                            }else {
                                this.setScale(scale,SMALLER);
                            }
                            beforeLenght = afterLenght;
                        }
                    }
                }
                */
                break;
        }
        return true;
    }


    /**
     * 实现处理缩放  
     */
    private void setScale(float temp,int flag) {

        if(flag==BIGGER) {
            this.setFrame(this.getLeft()-(int)(temp*this.getWidth()),
                    this.getTop()-(int)(temp*this.getHeight()),
                    this.getRight()+(int)(temp*this.getWidth()),
                    this.getBottom()+(int)(temp*this.getHeight()));
        }else if(flag==SMALLER){
            this.setFrame(this.getLeft()+(int)(temp*this.getWidth()),
                    this.getTop()+(int)(temp*this.getHeight()),
                    this.getRight()-(int)(temp*this.getWidth()),
                    this.getBottom()-(int)(temp*this.getHeight()));
        }
    }

    /**
     * 实现处理拖动  
     */
    private void setPosition(int left,int top,int right,int bottom) {
        this.layout(left,top,right,bottom);
    }
}
